1. Field of the Invention
The present invention relates to a recording apparatus and a recording medium conveying apparatus, and in particular, to the recording apparatus and recording medium conveying apparatus for recording on a front face (or front side surface) of a recording medium and then turning over the recording medium to record on backside (or rear side surface) thereof.
2. Description of the Related Art
Some proposals have been made so far as to an ink-jet apparatus capable of automatically performing two-sided recording. As for the apparatus disclosed by U.S. Pat. No. 6,332,068, recording paper is conveyed in a reverse direction by a paper feed roller after recording on a right face thereof, and is conveyed on an inverting route by a conveying roller in an inverting mechanism to which a driving force is transmitted from an LF motor for driving the paper feed roller. After a back end of the front face of the recording paper gets off the paper feed roller while conveying the recording paper on the inverting route, the paper feed roller rotates in a normal direction and conveys the recording paper in the normal direction to record on a backside thereof. In this case, the conveying roller in the inverting mechanism constantly rotates in the same direction whether the paper feed roller rotates in the normal direction or in the reverse direction. Therefore, even if the conveying roller rotates in the reverse direction while conveying the recording paper on the inverting route, the recording paper is conveyed in the same direction.
As for this recording apparatus, no measures are taken against floating of the end of the recording paper when recording on its backside. And it cannot record on a recording medium of high rigidity which cannot curve. A pinch roller press-contacted to the paper feed roller cannot be separated. And it does not perform so-called registration for rendering the end of the recording paper parallel with the paper feed roller as to the recording paper after a reversal.
In the case of a two-sided recording operation using the inverting mechanism as described above, it may happen that, when high-concentration recording is performed on a platen, a certain time for drying a recording portion on the front face is given, and the recording paper is reversed to record on its backside by conveying the end of the backside on the platen; the recording paper curls upward due to ink landed on in it in front face recording so that the recording paper contacts a carriage or a paper jam thereof occurs in an ejection roller portion. The paper may curl and the jam may occur on the front face recording depending on conditions such as a kind of the recording paper, a temperature of an environment in which the recording operation is performed and a gas flow rate.
If a discharger rate of the ink to the recording paper on the front face recording is reduced in order to curb the floating of the recording paper on backside recording, a recording quality level of the backside deteriorates.
If a paper holding member is mounted on the platen to hold the front and back of the recording paper for the sake of keeping the recording paper from floating when recording on its backside, the paper holding member interferes with frameless recording so that the frameless recording becomes no longer feasible or takes a conspicuously longer time.
To curb the floating of the backside of the recording paper in the above configuration, it is necessary to curl the end of the recording paper downward (direction of the platen) before the end of the recording paper is conveyedconveyed on the platen when recording on its backside. To curl the end of the recording paper downward easily, it is desirable to hold the recording paper at points as close to its end as possible in a conveying route curved as much as possible.
In the case where the recording paper is thick paper of which stiffness is relatively high such as a postcard, however, the recording paper is curled only a little when recording on its right face so that it is not essential to curl the end of the recording paper downward when recording on its backside.
As long as recording on the front face is performed in a portion at some distance from the back end of the front face (equivalent to the end of the backside) of the recording paper, there is not much influence of curling the end of the recording paper on the backside, it is not essential to curl the end of the recording paper downward when recording on its backside.
In recent years, there have been growing needs of recording on recording media of high rigidity such as a CD (Compact Disk) and a DVD (Digital Versatile Disk) by using the recording apparatus. However, there has been no proposal so far as to the recording apparatus equipped with the inverting mechanism for the two-sided recording and capable of recording on the recording media of such high rigidity not invertible by the inverting mechanism such as the CD and DVD. It can be pointed out, as one of the reasons for this, that placement of the conveying roller in the inverting mechanism and an approximately horizontal path for conveying the recording media of high rigidity is difficult.
If the end of the recording paper on which the recording is performed is curled toward the carriage, the recording paper rasps (or rubs) against the carriage and the recording medium loaded thereon. Then, it creates a situation in which the paper jam occurs while conveying the recording paper, the recording paper is stained by recording means or the recording paper rasps and damages the recording means.
The recording paper inverted by the inverting mechanism is conveyed on the conveying route for inversion, and so it is obliquely conveyed if there is resistance on the conveying route or variation in conveying force between the right and left conveying rollers. If so, the recording on the backside of the recording paper is obliquely performed to the recording paper.